SIGNIFICANCE The rate of cigarette smoking among people with psychiatric disorders remains exceedingly high; nearly two to four times as high as those in the general population. Patients with bipolar disorder may have the highest rates of smoking as compared with people with other psychiatric diagnoses. To date, there have been no treatment trials of adequate size to measure smoking cessation rates in people with bipolar disorder. If varenicline proves to be an effective in helping people with bipolar disorder to stop smoking, or even to reduce their smoking rates, this could play an important role in improving their health.